1. Field of the Invention
The present invention is related to a system for controlling indicator lights of a solid state disk, and more particularly related to a system for controlling indicator lights of a non-volatile memory express solid state disk.
2. Description of the Prior Art
The traditional hard disk drive (HDD) is a data storage device which uses magnetic heads to read and write data stored on a rotating disk. Thus, read and write speed of hard disk drives is mainly decided by the rotational speed of the disk and the data transferring speed of the interface. The typical hard disk drives in present have a rotational speed of 7200 revolution per minute (rpm), and some may achieve the rotational speed of 15000 rpm for higher read and write speeds, but the read and write speed of the hard disk drive has the limit in nature. In order to further enhance the read and write speeds, the solid state drive (SSD) using the so called flash memory was developed. The SSD has a read speed about 3 times the read speed of the HDD and a write speed about 1.5 times the write speed of the HDD, but a smaller power consumption, and also has the advantages of no noise generated, great vibration and shock resistance, and lower heat produced.
In the beginning, the SDD was designed to transfer data through the Serial Advanced Technology Attachment (SATA) interface specified by the Advanced Host Controller Interface (AHCI) standard. Because this is an interface designed for the traditional HDD, the data transferring speed of SSD would be influenced by the latency event when the storage control IC is dealing with the read and write operation of the disk drive. Thus, even though the SATA specification was developed from 2.0 revision (3 Gb/s, 300 MB/s) to 3.0 revision (6 Gb/s, 600 MB/s), it still cannot meet the data transferring capability of SSD. As a result, the data transferring ability of SSD would be restricted by the bandwidth of the data transferring interface.
In order to resolve the problem due to the limitation of data transferring interface bandwidth, the SSD in present tends to be made using the peripheral component interconnect express (PCIe) standard, i.e. a new SSD standard called non-volatile memory express (NVMe), to effectively improve the data transferring ability of SSD. Take the specification of PCIe 3.0 x8 as an example, the data transferring speed of PCIe 3.0 x8 is about ten times higher than that of the traditional SATA 3.0.
Regarding the other data transferring performance, in compared with the AHCI standard, which generates a latency about 2.5 micro second due to the need of accessing register four times when executing a command, NVMe interface simplifies the operation and thus it is not necessary to access the register when executing a command so as to show off the advantage of low latency. In addition, because the NVMe interface has a maximum queue depth of 65536 command queues and 65536 commands per queue, the advantage of parallel operation of NAND flash memories can be effectively exhibited. In contrast, AHCI interface only has a maximum queue of one command queue and 32 commands per queue. Thus, input/output operations per second (IOPS) of NVMe interface is much higher than that of AHCI interface.
As mentioned, although NVMe SSD is provided with extremely high data transferring speed, the SSD in present lacks the control module as the controller of the traditional HDD which is capable to parse the disk status and light up the corresponding indicator light. Thus, it would be difficult for the user to recognize the operation status of the SSD.